Psychosocial issues in breast cancer

Over the past year, increasing research attention has been devoted to the issue of women at increased risk of developing breast cancer. These articles focus on a range of issues from recruiting high-risk women into breast cancer trials to recommendations for assessment and counseling women with a family history of breast cancer. In addition, continuing research attention has focused on quality of life, symptom management, and articles related to physician-patient communication. This review summarizes and critiques publications in these areas, and it includes articles reviewing the status of research in psychosocial oncology.     

Sleep and breathing disorders in patients with brain stem lesions

Most information about the structures within the brain stem that modulate respiration and sleep are gathered from animal experiments. Therefore we examined 10 patients several weeks after an infarction of the brain stem by means of polysomnography and tested the chemosensitive drives of respiration. None of these patients complained about symptoms of sleep disordered breathing. In each case polysomnographic measurements and ventilatory response curves revealed pathologic findings. The respiratory response to CO2 was diminished or completely abolished in each patient. In some cases hypoventilation or disturbances of the respiratory rhythmicity could be seen. In several cases missing REM sleep, sleep fragmentation or the reduction of slow wave sleep were observed. The study indicates that on the base of results from animal research the comparison of morphological and pathophysiological data is helpful to gain a better understanding on the coupling of the respiratory system with sleep at the brain stem level as well as on the pathomechanism of sleep related breathing disorder.     

The mechanism of the poisoning of ammonia synthesis catalysts by oxygenates O2, CO and H2O: an in situ method for active surface determination

The effect of adding an oxygenated poison (O₂, CO or H₂O) to a hydrogen/nitrogen stream producing ammonia over a triply promoted (K₂O, CaO, Al₂O₃) commercial catalyst is not unsurprisingly rapidly to poison the catalyst. However, immediately the oxygenated poison reacts with the catalyst and before total poisoning has occurred, which in these experiments took 10 min, there was an explosive release of ammonia producing concentrations in the gas phase in excess of the equilibrium value. This is thought to be due to a convulsive reorganisation of the surface of the catalyst in forming regions of an oxide overlayer, resulting in the expulsion of the standing surface nitrogen atom coverage as ammonia. However, in contradistinction to the observation of complete poisoning of the triply promoted catalyst shortly after switching the water (2.9%) into the hydrogen/nitrogen stream, when polycrystalline iron was used as the catalyst, after the initial pulse of ammonia was observed, the small quantity of water (2.9%) in the hydrogen/nitrogen stream resulted in an increased rate ( ×3) of ammonia synthesis which declined only slightly over the twenty minute duration of the experiment. The difference in behaviour between the triply promoted catalyst and the polycrystalline iron is thought to be due to the relative ease of reduction of the latter, so that submonolayer quantities of oxide can be stabilised on the surface of the polycrystalline iron. The promoting effect of this oxide overlayer is either structural or electronic; no distinction can be made from these experiments. The technique of injecting either O₂ or CO into a hydrogen/nitrogen stream which is producing ammonia over promoted catalysts in quantities insufficient to cause complete poisoning and measuring the oxygen coverage of the catalyst to a measured decrease in the ammonia synthesis rate, appears to be a ready, in situ method for the determination of the active catalyst area.     

Electrochemical behaviour of 1024 mild steel in slightly alkaline bicarbonate solutions

The electrochemical behaviour of 1024 mild steel electrodes is investigated in the presence of 0.05–0.5 M sodium bicarbonate in aqueous solution at pH 8.9 and 25°C. Voltammograms are obtained with a rotating gold ring-mild steel electrode and the effect of the NaHCO3 concentration, the potential limits and the rotation speed of the disc electrode is considered. The voltammograms display an oxidation peak current at low potentials, a passivity region and a transpassive region at high potentials for the potential sweep in the anodic direction. The oxidation current in the passivity region is practically independent of the applied potential and the NaHCO3 concentration. The rate-determining step of the oxidation reaction in both the oxidation peak current region and the transpassive region is determined.     

块效应图像质量模糊评估标准

研究和讨论了图像质量评估方法,提出一种基于模糊推理的块效应评估标准。假设图像由平滑区域、边缘区域以及纹理区域等组成,而且不同的区域应采用不同的方法进行质量评估。在此基础上,给出了三个分别适用于不同区域的图像质量评估因子,并提出了一个灵活的模糊图像质量评估方法。此方法把块效应和图像本身具有的边缘分开,防止了边缘会被误认为是块效应。仿真结果表明,提出的标准对于不同的图像具有鲁棒性,有一般图像质量评价标准的性能。     

Long-range correlation properties of coding and noncoding DNA sequences: GenBank analysis

An open question in computational molecular biology is whether long-range correlations are present in both coding and noncoding DNA or only in the latter. To answer this question, we consider all 33301 coding and all 29453 noncoding eukaryotic sequences--each of length larger than 512 base pairs (bp)--in the present release of the GenBank to dtermine whether there is any statistically significant distinction in their long-range correlation properties. Standard fast Fourier transform (FFT) analysis indicates that coding sequences have practically no correlations in the range from 10 bp to 100 bp (spectral exponent beta=0.00 +/- 0.04, where the uncertainty is two standard deviations). In contrast, for noncoding sequences, the average value of the spectral exponent beta is positive (0.16 +/- 0.05) which unambiguously shows the presence of long-range correlations. We also separately analyze the 874 coding and the 1157 noncoding sequences that have more than 4096 bp and find a larger region of power-law behavior. We calculate the probability that these two data sets (coding and noncoding) were drawn from the same distribution and we find that it is less than 10(-10). We obtain independent confirmation of these findings using the method of detrended fluctuation analysis (DFA), which is designed to treat sequences with statistical heterogeneity, such as DNA's known mosaic structure ("patchiness") arising from the nonstationarity of nucleotide concentration. The near-perfect agreement between the two independent analysis methods, FFT and DFA, increases the confidence in the reliability of our conclusion.     

Perceptions of caring. Comparison of antepartum and postpartum patients

An exploratory, comparative survey design was used to describe and compare similarities and differences in perception of caring behaviors between hospitalized antepartum and short-stay postpartum patients. Forty-two patients completed the 63-item Caring Behavior Assessment instrument (CBA). The scale, based on Watson's theory of caring, contains seven categories. There were no statistically significant differences in age, education, gravida, or para between the two groups. Significantly more women in the postpartum group were married. There were no statistically significant differences or correlations in the total CBA scores and the demographic variables. No statistically significant differences in total CBA scores were found between antepartum participants and postpartum participants. These findings corroborate the results of "caring" studies in other patient populations, that satisfying basic needs--that is, evidence of technical knowledge and skills--is more important to patients than meeting higher order needs.     

The dental status of asthmatic British school children

Pancreatic cancer is a dismal disease. The 5-year overall survival ranges from 1% to 5%. Surgery is the only curative treatment available for this cancer, but it is indicated only in selected patients with a less than 4 cm tumor. In these patients, survival rate is about 30%. We have considered several aspects: the very difficult early diagnosis, the correct diagnostic flow chart, actual surgical procedures and new trends in biologic and genetic research. It is likely that better results can be achieved by defining an "early pancreatic cancer" and establishing how to detect it. This could be the wrigth one way is to significantly improve the survival of these patients.     

Proline isomerization-independent accumulation of an early intermediate and heterogeneity of the folding pathways of a mixed alpha/beta protein, Escherichia coli thioredoxin

Oxidized Escherichia coli thioredoxin (Trx) is a small protein of 108 residues with one disulfide bond (C32-C35 essentially involved in the activity) and no prosthetic moieties, which folds into a structural motif containing a central twisted beta-sheet flanked by helices that is found in many larger proteins. The kinetics of refolding of Trx in vitro have been investigated using a newly developed active site titration assay and continuous or stopped-flow (SF) methods in conjunction with circular dichroism (CD) and fluorescence (Fl) spectroscopy. These studies revealed the presence of early folding intermediates with "molten globule or pre-molten globule" characteristics. Measurements of the ellipticity at 222 nm indicated that about 68% of the total change associated with refolding occurred during the dead time (4 ms) of the stopped-flow instrument, suggesting the formation of substantial secondary structure. The reconstruction of the far-UV CD spectrum of the burst intermediate using combined continuous and stopped-flow methods showed the formation of a defined secondary structure that contains more beta-structure than the native state. Kinetic measurements using SF far-UV CD and Fl over a wide range (0.087-6 M) of GuHCl concentrations at two temperatures (6 and 20 degreesC) demonstrated that the population formed during the 4 ms dead time contained multiple species that are stabilized mainly by hydrophobic interactions and undergo further folding along alternative pathways. One of these species leads directly and rapidly to the native state as demonstrated by active site titration, while the two others fold into a fourth intermediate that is slowly converted to the native protein. Double-jump experiments suggest that the heterogeneity in folding behavior results from proline isomerizations occurring in the unfolded state. Conversely, the accumulation of the burst intermediate does not depend on proline isomerizations.     

Noise detection during bradycardia pacing with a hybrid nonthoracotomy implantable cardioverter defibrillator system: incidence and clinical significance

The purpose of this study was to prospectively evaluate the incidence of noise detection during bradycardia pacing by an FDA approved hybrid nonthoracotomy ICD system. An illustrative case report which prompted this investigation is provided. Backup bradycardia pacing by tiered therapy cardioverter defibrillators has been useful in preventing postshock bradycardia and occasionally for chronic rate support in bradycardic patients. Unexplained "noise" detected by real-time telemetry has been previously described during bradycardia pacing by a device utilizing automatic gain control for sensing. Eighteen patients were prospectively evaluated for noise detection during ventricular pacing by the ICD. Real-time telemetry was analyzed with each patient: (1) supine, (2) supine with deep inspiration/expiration, (3) supine during Valsalva, and (4) during a change in position from supine to sitting. Analysis of pacing threshold and lead impedance was made in each patient. Eleven of 18 patients had noise detected on real-time telemetry during bradycardia pacing. In 10 patients this was noted during deep inspiration/expiration, in 2 during Valsalva maneuver, and in 5 with position change. There was no evidence in any patient of lead malfunction nor any difference in pacing threshold or lead impedance between patients with noise detected versus those without it. Noise detection by an approved hybrid ICD system is common and may be due to the automatic gain control which maximizes sensitivity during bradycardia pacing. This may lead to clinically significant events, with both suppression of bradycardia pacing and triggering of tachycardia therapy in the absence of ventricular tachyarrhythmias in pacemaker-dependent patients.